In the adhesive industry, single site catalyzed polyolefin elastomers have generally been formulated with hydrogenated (H2HCRs) or fully aliphatic tackifiers for hot melt adhesives (HMA), to achieve superior adhesive performance. However, hydrogenated tackifiers are expensive to produce, and are currently in tight supply. Readily abundant rosin-based tackifiers (tackifiers derived from rosin) are lower in cost than H2HCRs tackifiers. There is a need for new adhesive compositions containing rosin-based tackifiers, and which have improved heat resistance and flexibility at room temperature and low temperatures (−17° C.).
Adhesive formulations are disclosed in the following references: U.S. Pat. Nos. 5,763,516, 5,441,999, 7,223,814, 7,645,829, 6,858,667, 5,458,982, 4,284,541, 7,645,829; International Publication No. WO2007146875; JP3046514B (Abstract), JP2052668B (Abstract), JP1029830B (Abstract), JP2008069295A (Abstract), JP61181882A (Abstract), JP55066981A (Abstract). However, as discussed above, there is a need for new adhesive compositions containing rosin-based tackifiers. There is a further need for such compositions that have improved heat resistance and flexibility at room temperature and low temperatures (−17° C.). These needs have been met by the following invention.